Patterns for Integrating and Exploiting Some Non-Functional Properties in Hierarchical Software Components

Abstract

Providing powerful and fine-grained capabilities for the analysis and management of non-functional properties is a major challenge for component-based software systems. In this paper, we propose integration patterns for nonfunctional properties of hierarchical software components. These patterns are based on a classification of low-level non-functional properties, which takes into account their nature and lifecycle. They make explicit the implementation of these properties in relation with components and can be used to develop some forms of compositional reasoning. The proposals are exploited in non-functional contract negotiation by enabling a negotiation process to be precisely propagated down the component hierarchy.

QoS contract preservation through dynamic reconfiguration: A formal semantics approach

“…QoS contracts constitute a natural and effective means for capturing this kind of contextdependent requirements, such as those on performance, availability and confidentiality [1,2]. Several specifications [3,4], languages [5,6], formal semantics [7,8] and models [9,10,11,12], among others, have been proposed to specify, model and support the QoS contracts elements, the relationship among QoS provisions and requirements, and enforcement mechanisms. However, despite these many advances, the development of a sound theory to preserve QoS contracts in component-based systems still remains an open problem with at least two important challenges.…”

QoS Contract-Aware Reconfiguration of Component Architectures Using E-Graphs

“…Nonetheless, providing a component-based software system with reconguration capabilities to preserve its QoS contracts presents several diculties: (i) the expression of the QoS contract itself, given that it must specify the dierent inria-00525438, version 1 -11 Oct 2010 Author manuscript, published in "7th International Workshop on Formal Aspects of Component Software (2010)" contextual conditions on the contracted QoS property, and the corresponding guaranteeing actions to be performed in case of the QoS contract disruption [13,15]; (ii) in contraposition to functional contracts, which can be checked statically, QoS contracts are aected by global and extra-functional behaviour that must be evaluated at runtime. This evaluation requires also dynamic monitoring schemes, dierent to the static ones usually found in current systems [7]; (iii) several reconguration strategies can be used to address each desirable condition on a QoS property. These strategies are provided by dierent disciplines (e.g., those related to performance, reliability, availability and security), and constitute a rich knowledge base to be exploited.…”